1. Field of the Invention
The present invention is directed to a x-ray radiator of the type containing a rotating bulb tube which rotates within a radiator housing filled with a fluid coolant, with a cooling system for the coolant including an external heat exchanger.
2. Description of the Prior Art
When the waste heat produced in the generation of x-rays in an x-ray radiator is not too great, natural convection can be exploited in order to transport the heat away from the tube. Given higher tube powers, however, the heat transfer coefficients that can be achieved are too low to rely on convention. Only higher flow rates of the coolant then provide alleviation, for which purpose circulating pumps have been conventionally utilized in the cooling system, which produce a correspondingly high coolant circulation.
The employment of such circulating pumps causes not only increased costs, but the susceptibility of such circulating pumps to failure represents a further cause that can lead to an outage of the x-radiator.
Avoidance of the use of such pumps is achieved in a rotating bulb tube disclosed in German Patent 881 974, by providing a ribbing on the rotating tube, or the rotating tube can be provided with propellers for conveying the coolant. These measures, however, lead to a complicated and expensive structure of the rotating tube.